A central office in a telephone system contains banks of batteries for powering the equipment in the central office upon a failure of the external power supply. Power cables for interconnecting the batteries and the telephone equipment are supported on overhead racks. The racks are ladder shaped structures that extend horizontally across beams defined by framing channels. The framing channels are suspended from the ceiling by threaded rods that are anchored to the ceiling.
Pulleys are used to guide the power cables over the racks when the power cables are being installed. Specifically, the pulleys are clamped onto the racks or the framing channels at locations suitable for the particular installation of power cables. The pulleys are removed when the installation is complete.